提交 c4f895cb 编写于 作者: J Jens Axboe

[PATCH] splice: cleanup the SPLICE_F_NONBLOCK handling

- generic_file_splice_read() more readable and correct
- Don't bail on page allocation with NONBLOCK set, just don't allow
  direct blocking on IO (eg lock_page).
Signed-off-by: NJens Axboe <axboe@suse.de>
上级 91ad66ef
......@@ -278,14 +278,6 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
*/
page = find_get_page(mapping, index);
if (!page) {
/*
* If in nonblock mode then dont block on
* readpage (we've kicked readahead so there
* will be asynchronous progress):
*/
if (flags & SPLICE_F_NONBLOCK)
break;
/*
* page didn't exist, allocate one
*/
......@@ -307,6 +299,13 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
* If the page isn't uptodate, we may need to start io on it
*/
if (!PageUptodate(page)) {
/*
* If in nonblock mode then dont block on waiting
* for an in-flight io page
*/
if (flags & SPLICE_F_NONBLOCK)
break;
lock_page(page);
/*
......@@ -400,17 +399,20 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
while (len) {
ret = __generic_file_splice_read(in, ppos, pipe, len, flags);
if (ret <= 0)
if (ret < 0)
break;
else if (!ret) {
if (spliced)
break;
if (flags & SPLICE_F_NONBLOCK) {
ret = -EAGAIN;
break;
}
}
*ppos += ret;
len -= ret;
spliced += ret;
if (!(flags & SPLICE_F_NONBLOCK))
continue;
ret = -EAGAIN;
break;
}
if (spliced)
......
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